WITH ENVIRONMENTAL-CONTROL, THE EFFECTS OF RACE AND SEX ON BLOOD-PRESSURE REGULATORY MECHANISMS APPEAR DIMINISHED

To assess environmental control on autonomic parameters between race a nd sex, we studied cross-sectionally, 119 West Point cadets of both se xes and of African-American and Caucasian descent. Specifically, heart period variability (HPV) and baroreceptor sensitivity index (BRSI) we re assessed non-invasively. All participants had lived at the Academy for at least 1 year, had similar diets, ages, fitness status, access t o medical care and educational backgrounds. Familial aggregation of hy pertension was 46% for African-American and 30% for Caucasian, respect ively. Autonomic outflow was assessed using the magnitude of the respi ratory sinus arrhythmia (RSA) during sitting, standing and augmented b reathing. Autocorrelations on 64 successive heart periods provided low frequency (LF) or high frequency (HF) distributions. The ratio of LF over HF was considered representative of sympathovagal balance. Barore ceptor sensitivity (BRSI) was assessed by recording cardiac decelerati on in response to a Val-salva-induced increase in BP. Analysis of vari ance failed to reveal significant differences in any of these BP regul atory mechanisms between any of the groups. Prior investigations faile d to control for the many environmental factors mentioned above and ha ve therefore indicated significant epidemiological differences in the occurrence of hypertension between different races. Our results strong ly suggest that environmental control seems to be an important modulat or in the pathogenic mosaic of autonomic derangement, and should be st rongly considered in future research.